What is a common sign that indicates poor ventilation in an attic?

A common sign of poor ventilation in an attic is the presence of ice dams on the roof during winter. Ice dams form when warm air from the attic escapes and melts the snow on the roof. As the meltwater flows down to the colder edges of the roof, it refreezes, creating a dam of ice. Poor ventilation can trap heat in the attic, exacerbating this problem. If ventilation were adequate, the temperature of the roof would remain more consistent, preventing the melting and refreezing cycle that causes ice dams.

In contrast, while excessive dust accumulation, improper insulation, and increased insect activity can indicate various issues within an attic or building, they are not direct indicators of poor ventilation. These signs can arise from other causes, such as lack of routine maintenance or infestation, making them less specific when diagnosing ventilation problems.